Additive manufacturing (AM) technologies have demonstrated a promising material efficiency potential in comparison to traditional material removal processes. A new directed energy deposition (DED) category AM process called wire arc additive manufacturing (WAAM) is evolving due to its benefits which include faster build rates, capacity to build large volumes, and inexpensive feedstock materials and machine tools compared to more technologically mature powder-based AM technologies. However, WAAM products present challenges like poor surface finish and lower dimensional accuracy compared to powder-based processes or machined parts, prevalence of thermal distortions, residual stresses, and defects like porosity, cracks, and humping, often requiring post-processing operations like finish machining and heat treatment. These post-processing operations add to the production cost and environmental footprint of WAAM-built parts. Therefore, considering the opportunities and challenges presented by WAAM, this paper analyses the environmental impact, production costs, and mechanical properties of WAAM parts and compares them with those achieved by laser powder bed fusion (LPBF) and traditional computer numerical control (CNC) milling. A high-strength low-alloy steel (ER70S) mechanical part with medium complexity was fabricated using WAAM. Based on the data collected during this experiment, environmental impact and cost models were built using life cycle assessment and life cycle costing methodologies. WAAM was observed to be the most environmentally friendly option due to its superior material efficacy than CNC milling and has a better energy efficiency than LPBF. Also, WAAM was the most cost-friendly option when adopted in batch production for batch sizes above 3. The environmental and cost potential of WAAM is amplified when used for manufacturing large products, resulting in significant material, emission, and cost savings. The fabricated WAAM part demonstrated good mechanical properties comparable to that of cast/forged material. The methodology and experimental data presented in this study can be used to calculate environmental impacts and costs for other products and can be helpful to manufacturers in selecting the most ecofriendly and cost-efficient manufacturing process.

The traditional method of manufacturing propellant tanks for rockets and spaceships involves significant amounts of forging, and machining, making it expensive and environmentally unfriendly. A novel approach for manufacturing propellant tanks that reduces the need for machining and friction stir welding processes has been presented in this paper. This approach involves manufacturing a tank half starting from a single metal plate, using innovative and advanced metal forming processes such as hot stretch forming, magnetic pulse forming, hub forming, and integrated stiffened cylinder (ISC) flow forming followed by orbital welding of two tank halves. A life cycle assessment (LCA) study was conducted in accordance with ISO 14044:2006 standard using the ReCiPe 2016 Midpoint (H) method to compare the environmental impacts of the traditional and newly developed approaches for manufacturing propellant tanks. The results of the LCA study showed that the new approach based on advanced forming technologies reduced carbon footprint by 40%, cumulative energy demand by 35%, water footprint by 17%, and materials waste by 4% compared to traditional manufacturing. The lower environmental impact of the new approach was attributed to a decrease in friction stir welding requirements due to the implementation of advanced forming techniques that enable integrated tank production. This lowered the overall energy consumption in the novel approach by a factor of 1.5 and in turn resulted in lower environmental impact compared to traditional forging and machining-based method. Furthermore, a futuristic scenario that involves in-house tank production using the novel approach with minimal transportation of inventories was also simulated. Based on the LCA results, it was seen that the newly developed approach for manufacturing propellant tanks was more environmentally friendly than the traditional approach and its environmental footprint could be further reduced by implementing the futuristic scenario with minimal transportation. This novel approach is also expected to reduce the lead time and production cost of manufacturing a propellant tank. Hence, future efforts in cost assessment and further optimization of raw material and energy usage are recommended.

Purpose: Additive manufacturing (AM) is gaining attention in industry due to its benefits like the ability to fabricate complex geometries, reduced material wastage, minimal tooling, and shorter lead times. From a sustainability perspective, the environmental and economic dimensions of AM have been studied in the literature, but its social dimensions remain relatively unexplored. This study presents a social organizational life cycle assessment (SO-LCA) of a wire arc additive manufacturing (WAAM) technology-based company that offers production and fabrication services in Belgium. Method: The scope of this investigation includes phases like production of primary material, i.e., steelmaking, production of feedstock wires from steel, WAAM production, and post-processing to fabricate/repair components. The relevant social indicators, social impact subcategories, and stakeholders are identified based on the S-LCA guidelines and methodological sheets provided by the United Nations Environment Programme/Society of Environmental Toxicology and Chemistry (UNEP/SETAC). The social inventory data are collected from interviews with top management, company reports, as well as national and international databases. Based on the data obtained, social indicators are evaluated using the reference scale method on a scale of 1–5 (with 1 = highly negative social impact and 5 = highly positive social impact). An aggregation model was also developed to average individual social indicator scores at both the stakeholder level and across the entire life cycle. Results: Overall, a positive impact on the stakeholder groups such as workers, society, and suppliers while the impact on customers is neutral. However, a negative impact is seen on the stakeholder group local community due to unhealthy air quality caused by higher concentrations of fine dust (particulate matter 2.5) and nitrous oxide (NO_x) emissions, especially from the steel-making phase. Conclusions: The issues of social concern are identified for each stakeholder and suggestions for improvement of their social performance are discussed. Limitations of the study include the sensitivity of results to geographical and legislative context, exclusion of mining activities in steel production, and lack of site-specific data for certain indicators. Hence, future research should focus on the integration of mining activities, obtaining more site-specific data, and studying the influence of different geographical and legislative contexts on the company’s social performance.